Avalanche Forecast
Issued: Apr 22nd, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs, Cornices and Wind Slabs.
jsmith,
Avalanche Canada
Numerous very large deep persistent slab avalanches have been reported on a variety of aspects in the alpine.
Avoid steep, rocky, shallow, or thin-to-thick areas in the snowpack where triggering slabs is more likely.
Summary
Confidence
Avalanche Summary
Numerous naturally triggered very large (up to size 3.5) deep persistent slab avalanches were reported on a variety of aspects in the alpine on Friday. They failed on either a crust/facet layer 100+cm deep or weak facets at the bottom of the snowpack. Follow the link on this MIN for the photos of these notable avalanches.
Observations are limited at this time of year, please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.
Snowpack Summary
A weak layer of crust/facets down 100+ cm and/or weak facets at the bottom of the snowpack have recently become reactive.
Warm temperatures and/or solar radiation will increase the likelihood of triggering very large avalanches.
Cornices are large and loom over slopes below like gargoyles.
Recent wind has varied in direction so watch for lingering wind slabs on all aspects at upper elevations.
Weather Summary
Saturday Night
Cloudy with isolated flurries; 0-3 cm / 20 km/h southeast ridgetop wind / Temperature at treeline around -3 C / Freezing level 700 m
Sunday
Mostly cloudy with isolated flurries; 5-10 cm / 30 km/h southeast ridgetop wind / Temperature at treeline around 0 C / Freezing level 1000 m
Monday
Mix of sun and cloud with flurries; 5-10 cm / 30 km/h south ridgetop wind / Temperature at treeline around -3 C / Freezing level 700 m
Tuesday
Mix of sun and cloud / 30 km/h south ridgetop wind / Temperature at treeline around -2 C / Freezing level 800 m
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
- Cornice failure may trigger large avalanches.
- Recent wind has varied in direction so watch for wind slabs on all aspects.
Problems
Deep Persistent Slabs
A weak layer of crust/facets down 100+ cm and/or weak facets at the bottom of the snowpack have recently become reactive.
Warm temperatures and/or solar radiation will increase the likelihood of triggering very large avalanches.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Cornices are very large and loom over slopes below like gargoyles. Cornice falls may trigger large avalanches on the slopes below.
Aspects: North, North East, East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Wind Slabs
Recent wind has varied in direction so watch for lingering wind slabs on all aspects at upper elevations.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 23rd, 2023 4:00PM
